Game apps for iOS pummeled Android game apps when it came to revenue for the fourth quarter, but Android is growing quickly.

According to App Annie's Index, iOS games earned 3.5 times the revenue of Android games in Q4 2012. The iOS App Store increased its overall revenue by 20 percent from Q3 to Q4 2012 while the Google Play store doubled its app revenue in the same time period. However, iOS still raked in more cash.